Hello Davidgal & DomH, thanks for your answers!
moving it manually to /usr/share/openGribs/XyGrib/data instead of /usr/share/XyGrib/data fixed indeed the problem.
Regarding the discussion 'Use Linux Installer'....I read the Thread
opengribs.org/en/forum/xygrib-support/67...ore-official-release ...and I prefer OBS packages over any other means. Considering you can build for nearly all other distros, it is quite a neat tool. Have to admit, I'm not a fan of flatpack, snap and others as well